The present disclosure relates generally to an improvement in the precision and accuracy of sortation in material handling systems, and is particularly directed to an apparatus and method that consistently and reliably delivers articles to the desired discharge location at the desired time. The innovation will be specifically disclosed in connection with a unit sortation system which includes a crossbelt carrier.
Goals of sortation systems are accuracy and the maximization of throughput of articles. While increasing conveyance speed will increase throughput, the difficulty, and therefore the importance, of maintaining accuracy increases as the speed of conveyance increases.
While there are many aspects of accuracy, it ultimately comes down to overall system accuracy—getting each article to its intended discharge location. Sortation accuracy directly affects the overall system accuracy: inaccuracies are manifested by articles that are discharged to the wrong location (e.g., misdirected articles), jams, and by non-discharged product. In order to discharge articles to an intended location, the articles must be delivered to a designated discharge location at a specified time, and within acceptable tolerance ranges. As speed of conveyance increases the acceptable tolerance ranges decreases.
There are many systems and conditions upstream of the point of induction that directly influence sortation accuracy. In addition, the precision and accuracy of the systems between the point of induction and the discharge location have a substantial influence on the overall system accuracy and throughput. The present innovation may be used in a unit sortation system, such as crossbelt and tilt tray sorter, and more particularly is disclosed in connection with a crossbelt sortation subsystem system. Unit sorters are also known as loop sorters.
The location of an article on a carrier of a unit sortation conveyor is directly related to the ability to accurately deliver the article to its intended discharge location. Prior art solutions for crossbelt sorters have included the requirement to take a positive corrective action in order to reposition the article on the carrier laterally so as to relocate the article to the carrier's lateral center prior to instructing the carrier to discharge. This one dimensional adjustment becomes less effective as carrier width and carrier speed increases, and is not adequate to produce the desired accurate and precise discharge of articles. Such a solution is disadvantageous since it requires a wider discharge chute, consuming valuable floor space proximate to the sortation machine, thereby reducing the number of available discharge locations.
The present innovation results in articles being delivered through a selected point in space on a discharge trajectory, resulting, in the embodiment disclosed, in the article's own inertia in combination with gravity carrying that article to a selected destination.
Although an embodiment described herein in comprises a crossbelt unit sortation conveyor system, it will be understood that the present innovation is not limited in use or application thereto.